Hi,
I'll agree with Tom on this one, too. UHF connector and adapter losses at
HF frequencies are negligible. Please see the towertalk thread on this
subject from just a few months ago. In this excellent discussion was, what
I thought to be, a ham's rather controlled university experiment to
discover the truth on this very same subject.
As long as you follow these general guidelines, you shouldn't have too many
problems:
1. Ensure the connectors are mechanically and electrically sound - one's
that have the center conductor and the shield soldered, along with a
quality barrel adaptor.
2. Waterproof the splices with something like the Scotch 70 series,
self-fusing, rubber, electrical tape or equivalent. Possibly cover this
first layer with regular electrical tape or heat-shrink.
3. Carefully select your physical placement of these splices to prevent
mechanical integrity issues later.
Install the lower loss cable, and enjoy the fruits of your labor.
A watt saved, is a watt radiated.
73 de Steve, KZ9G
At 10:57 PM 5/28/2002 -0400, you wrote:
> > ...........somebody ages ago pointed out that on one install they had
> > improved (decreased) their feedline loss by using some better hard
> > line for part of the run - as it turned out the adding of two barrel
> > connectors (4 connections) probably offset all of his gains!
>
>Contrary to folklore and wive's tales that claim silly things like
>"0.5dB per splice" or other such nonsense, connectors can be
>considered lossless at HF.
>
>Another bit of folklore is that an S-unit is 6dB. Most S meters are
>around 3-5dB per S-unit near the top of the scale, but down low on
>the scale an S-unit can be as little as 1dB!
>
>S-meters aside, 1 dB can be a remarkable difference in copy when a
>signal is near noise or QRM level.
>
> This meant the problem was after the next splice point which would
> > have been at the top of the tower about 135 feet up.....
>
>The biggest problem is not installing the connectors correctly, over-
>tightening or under-tightening them, and waterproofing them
>incorrectly. UHF connectors are very forgiving of installation
>errors, such as over-tightening or placed under stress.
>
>Splices aren't a problem if they are made correctly and waterproofed
>properly. As a matter of fact, I've never had a splice fail or cause
>problems and there are sometimes five or six of them in a run to an
>antenna.
>
>I don't worry at all about splices or connectors, and I use them at
>any point where I might need access to the cable. I never give it a
>second thought at all. If they are lossy at all, 1500 watts will melt
>em right down so any problems with cheap connectors show up right
>away.73, Tom W8JI
>W8JI@contesting.com
>
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